Q fever in the Netherlands - 2007-2010: what we learned from the largest outbreak ever

EirA Is a Novel Protein Essential for Intracellular Replication of Coxiella burnetii

The zoonotic bacterial pathogen Coxiella burnetii is the causative agent of Q fever, a febrile illness which can cause a serious chronic infection. C. burnetii is a unique intracellular bacterium which replicates within host lysosome-derived vacuoles. The ability of C. burnetii to replicate within this normally hostile compartment is dependent on the activity of the Dot/Icm type 4B secretion system. In a previous study, a transposon mutagenesis screen suggested that the disruption of the gene encoding the novel protein CBU2072 rendered C. burnetii incapable of intracellular replication. This protein, subsequently named EirA (essential for intracellular replication A), is indispensable for intracellular replication and virulence, as demonstrated by infection of human cell lines and in vivo infection of Galleria mellonella The putative N-terminal signal peptide is essential for protein function but is not required for localization of EirA to the bacterial inner membrane compartment and axenic culture supernatant. In the absence of EirA, C. burnetii remains viable but nonreplicative within the host phagolysosome, as coinfection with C. burnetii expressing native EirA rescues the replicative defect in the mutant strain. In addition, while the bacterial ultrastructure appears to be intact, there is an altered metabolic profile shift in the absence of EirA, suggesting that EirA may impact overall metabolism. Most strikingly, in the absence of EirA, Dot/Icm effector translocation was inhibited even when EirA-deficient C. burnetii replicated in the wild type (WT)-supported Coxiella containing vacuoles. EirA may therefore have a novel role in the control of Dot/Icm activity and represent an important new therapeutic target.

Relationship between Coxiella burnetii (Q fever) antibody serology and time spent outdoors

BACKGROUND/AIM

From 2007 through 2010, the Netherlands experienced the largest recorded Q fever outbreak to date. People living closer to Coxiella burnetii infected goat farms were at increased risk for acute Q fever. Time spent outdoors near infected farms may have contributed to exposure to C. burnetii. The aim of this study was to retrospectively evaluate whether hours/week spent outdoors, in the vicinity of previously C. burnetii infected goat farms, was associated with presence of antibodies against C. burnetii in residents of a rural area in the Netherlands.

METHODS

Between 2014-2015, we collected C. burnetii antibody serology and self-reported data about habitual hours/week spent outdoors near the home from 2494 adults. From a subgroup we collected 941 GPS tracks, enabling analyses of active mobility in the outbreak region. Participants were categorised as exposed if they spent time within specified distances (500m, 1000m, 2000m, or 4000m) of C. burnetii infected goat farms. We evaluated whether time spent near these farms was associated with positive C. burnetii serology using spline analyses and logistic regression.

RESULTS

People that spent more hours/week outdoors near infected farms had a significantly increased risk for positive C. burnetii serology (time spent within 2000m of a C. burnetii abortion-wave positive farm, OR 3.6 (1.2-10.6)), compared to people spending less hours/week outdoors.

CONCLUSIONS

Outdoor exposure contributed to the risk of becoming C. burnetii serology positive. These associations were stronger if people spent more time near C. burnetii infected farms. Outdoor exposure should, if feasible, be included in outbreak investigations.

Biogenesis of the Spacious Coxiella-Containing Vacuole Depends on Host Transcription Factors TFEB and TFE3

Coxiella burnetii is an obligate intracellular bacterial pathogen that replicates inside the lysosome-derived Coxiella-containing vacuole (CCV). To establish this unique niche, C. burnetii requires the Dot/Icm type IV secretion system (T4SS) to translocate a cohort of effector proteins into the host cell, which modulate multiple cellular processes. To characterize the host-pathogen interactions that occur during C. burnetii infection, stable-isotope labeling by amino acids in cell culture (SILAC)-based proteomics was used to identify changes in the host proteome during infection of a human-derived macrophage cell line. These data revealed that the abundances of many proteins involved in host cell autophagy and lysosome biogenesis were increased in infected cells. Thus, the role of the host transcription factors TFEB and TFE3, which regulate the expression of a network of genes involved in autophagy and lysosomal biogenesis, were examined in the context of C. burnetii infection. During infection with C. burnetii, both TFEB and TFE3 were activated, as demonstrated by the transport of these proteins from the cytoplasm into the nucleus. The nuclear translocation of these transcription factors was shown to be dependent on the T4SS, as a Dot/Icm mutant showed reduced nuclear translocation of TFEB and TFE3. This was supported by the observation that blocking bacterial translation with chloramphenicol resulted in the movement of TFEB and TFE3 back into the cytoplasm. Silencing of the TFEB and TFE3 genes, alone or in combination, significantly reduced the size of the CCV, which indicates that these host transcription factors facilitate the expansion and maintenance of the organelle that supports C. burnetii intracellular replication.

Comparison of two new in-house Latex Agglutination Tests (LATs), based on the DnaK and Com1 synthetic peptides of Coxiella burnetii, with a commercial indirect-ELISA, for sero-screening of coxiellosis in bovines

The in-house developed DnaK and Com1 synthetic peptide-based Latex Agglutination Tests (LATs) were comparatively evaluated with commercial indirect-ELISA kit, to provide a rapid, economical and onsite field applicable test for seroscreening of coxiellosis in bovines.

New Genotypes of Coxiella burnetii Circulating in Brazil and Argentina

Coxiella burnetii, the zoonotic agent of Q fever, has a worldwide distribution. Despite the vast information about the circulating genotypes in Europe and North America, there is a lack of data regarding C. burnetii strains in South America. Here, we show the presence of novel multispacer sequence typing (MST) genotypes of C. burnetii in two clusters detected in Brazil and Argentina that seem to be distant in parenthood. Argentinian strains isolated from a tick belongs to a new phylogenetic branch of C. burnetii, and the Brazilians strains may be related to MST 20 and 61. Multilocus variable number tandem repeats analysis (MLVA) typing provided a deeper resolution that may be related to host clusters of bovines, caprine, ovine, and ticks. Our results corroborate with the reports of geotypes of C. burnetii. Thus, we highlight the need for more genotyping studies to understand the genetic diversity of C. burnetii in South America and to confirm the hypothesis of host-related genotypes. We also emphasize the importance of virulence studies for a better understanding of Q fever in the region, which may help in surveillance and disease prevention programs.

The European Union One Health 2018 Zoonoses Report

This report of the European Food Safety Authority and the European Centre for Disease Prevention and Control presents the results of zoonoses monitoring activities carried out in 2018 in 36 European countries (28 Member States (MS) and 8 non‐MS). The first and second most commonly reported zoonoses in humans were campylobacteriosis and salmonellosis, respectively. The European Union (EU) trend for confirmed human cases of these two diseases was stable during 2014–2018. The proportion of human salmonellosis cases due to Salmonella Enteritidis was at the same level in 2018 as in 2017. Of the 27 reporting MS, 16 met all Salmonella reduction targets for poultry, whereas 11 MS failed meeting at least one. The EU flock prevalence of target Salmonella serovars in breeding hens, laying hens, broilers and fattening turkeys decreased during recent years but stalled in breeding turkeys. Salmonella results from Competent Authorities for pig carcasses and for poultry tested through National Control Programmes were more frequently positive compared with food business operators. Shiga toxin‐producing Escherichia coli (STEC) infections in humans were the third most commonly reported zoonosis in the EU and increased from 2014 to 2018. Yersiniosis was the fourth most frequently reported zoonosis in humans in 2018 with a stable trend in 2014–2018. The number of reported confirmed listeriosis cases further increased in 2018, despite Listeria rarely exceeding the EU food safety limit tested in ready‐to‐eat food. In total, 5,146 food‐ and waterborne outbreaks were reported. Salmonella was the most commonly detected agent with S. Enteritidis causing one in five outbreaks. Salmonella in eggs and egg products was the highest risk agent/food pair. A large increase of human West Nile virus infections was reported in 2018. The report further updates on bovine tuberculosis, Brucella, Trichinella, Echinococcus, Toxoplasma, rabies, Coxiella burnetii (Q fever) and tularaemia.

Com1 as a Promising Protein for the Differential Diagnosis of the Two Forms of Q Fever

Coxiella burnetii is the causative agent of acute and chronic Q fever in humans. Although the isolates studied so far showed a difference in virulence potential between those causing the two forms of the disease, implying a difference in their proteomic profile, the methods used so far to diagnose the two forms of the disease do not provide sufficient discriminatory capability, and human infections may be often misdiagnosed. The aim of the current study was to identify the outer membrane Com1 (CBU_1910) as a candidate protein for serodiagnostics of Q fever. The protein was cloned, expressed, purified, and used as an antigen in ELISA. The protein was then used for the screening of sera from patients suffering from chronic Q fever endocarditis, patients whose samples were negative for phase I immunoglobulin G (IgG), patients for whom at least one sample was positive for phase I IgG, and patients suffering from any kind of rheumatoid disease. Blood donors were used as the control group. Following statistical analysis, 92.4% (122/132) of the samples tested agreed with the negative clinical diagnosis, and 72.2% (26/36) agreed with the positive clinical diagnosis. Moreover, a significant correlation to the presence of the disease (p = 0.00) was calculated. The results support the idea that a Com1 antigen-based serodiagnostic test may be useful for differential diagnosis of chronic Q fever. Further studies are required to compare more immunogenic proteins of the bacterium against samples originating from patients suffering from different forms of the disease.

Seroepidemiological and molecular investigation of spotted fever group rickettsiae and Coxiella burnetii in Sao Tome Island: A One Health approach

Spotted fever group rickettsiae (SFGR) and Coxiella burnetii are intracellular bacteria that cause potentially life-threatening tick-borne rickettsioses and Q fever respectively. Sao Tome and Principe (STP), small islands located in the Gulf of Guinea, recently experienced a dramatic reduction in the incidence of malaria owing to international collaborative efforts. However, unexplained febrile illnesses persist. A One Health approach was adopted to investigate exposure to SFGR and C. burnetii in humans and examine the diversity of these bacteria in ticks parasitizing domestic ruminants. A cross-sectional human serological study was conducted in Agua Grande district in Sao Tome Island from January to March 2016, and ticks were collected from farmed domestic ruminants in 2012 and 2016. In total, 240 individuals varying in age were randomly screened for exposure to SFGR and C. burnetii by indirect immunofluorescence assay. Twenty of 240 individuals (8.3%) were seropositive for SFGR (4 for Rickettsia africae and 16 for R. conorii) and 16 (6.7%) were seropositive for C. burnetii. Amblyomma astrion were collected exclusively in 2012, as were A. variegatum in 2016 and Rickettsia spp. were detected in 22/42 (52.4%) and 49/60 (81.7%) respectively. Sequence analysis of multiple gene targets from Rickettsia spp. detected in ticks suggests the presence of a single divergent R. africae strain (Sao Tome). While no ticks were found positive for C. burnetii, Coxiella-like endosymbionts were detected in nearly all ticks. This is the first study in STP to provide serological evidence in humans of SFGR and C. burnetii and additional molecular evidence in ticks for SFGR, which may be responsible for some of the unexplained febrile illnesses that persist despite the control of malaria. Future epidemiological studies are needed to confirm the occurrence and risk factors associated with SFG rickettsioses and Q fever in both humans and animals.

Current perspectives on the transmission of Q fever: Highlighting the need for a systematic molecular approach for a neglected disease in Africa

Q fever is a bacterial worldwide zoonosis (except New Zealand) caused by the Gram-negative obligate intracellular bacterium Coxiella burnetii (C. burnetii). The bacterium has a large host range including arthropods, wildlife and companion animals and is frequently identified in human and livestock populations. In humans, the disease can occur as either a clinically acute or chronic aetiology, affecting mainly the lungs and liver in the acute disease, and heart valves when chronic. In livestock, Q fever is mainly asymptomatic; however, the infection can cause abortion, and the organism is shed in large quantities, where it can infect other livestock and humans. The presence of Q fever in Africa has been known for over 60 years, however while our knowledge of the transmission routes and risk of disease have been well established in many parts of the world, there is a significant paucity of knowledge across the African continent, where it remains a neglected zoonosis. Our limited knowledge of the disease across the African sub-continent have relied largely upon observational (sero) prevalence studies with limited focus on the molecular epidemiology of the disease. This review highlights the need for systematic studies to understand the routes of C. burnetii infection, and understand the disease burden and risk factors for clinical Q fever in both humans and livestock. With such knowledge gaps filled, the African continent could stand a better chance of eradicating Q fever through formulation and implementation of effective public health interventions.

Notification data and criteria during a large Q-fever epidemic reassessed

From 2007 to 2010, the largest reported Q-fever epidemic occurred in the Netherlands with 4026 notified laboratory-confirmed cases. During the course of the epidemic, health-seeking behaviour changed and awareness among health professionals increased. Changes in laboratory workflows were implemented. The aim of this study was to analyse how these changes instigated adjustments of notification criteria and how these adjustments affected the monitoring and interpretation of the epidemic. We used the articles on laboratory procedures related to the epidemic and a description of the changes that were made to the notification criteria. We compared the output of a regional laboratory with notifications to the regional Public Health Service and the national register of infectious diseases. We compared the international notification criteria for acute Q-fever. Screening with ELISA IgM phase II and PCR was added to the diagnostic workflow. In the course of the epidemic, serology often revealed a positive IgG/IgM result although cases were not infected recently. With increasing background seroprevalence, the presence of IgM antibodies can only be suggestive for acute Q-fever and has to be confirmed either by seroconversion of IgG or a positive PCR result. Differences in sero-epidemiology make it unlikely that full harmonisation of notification criteria between countries is feasible.

Zoonoses under our noses

One Health is an effective approach for the management of zoonotic disease in humans, animals and environments. Examples of the management of bacterial zoonoses in Europe and across the globe demonstrate that One Health approaches of international surveillance, information-sharing and appropriate intervention methods are required to successfully prevent and control disease outbreaks in both endemic and non-endemic regions. Additionally, a One Health approach enables effective preparation and response to bioterrorism threats.

The European Union summary report on trends and sources of zoonoses, zoonotic agents and food-borne outbreaks in 2017

This report of the European Food Safety Authority and the European Centre for Disease Prevention and Control presents the results of zoonoses monitoring activities carried out in 2017 in 37 European countries (28 Member States (MS) and nine non-MS). Campylobacteriosis was the commonest reported zoonosis and its EU trend for confirmed human cases increasing since 2008 stabilised during 2013-2017. The decreasing EU trend for confirmed human salmonellosis cases since 2008 ended during 2013-2017, and the proportion of human Salmonella Enteritidis cases increased, mostly due to one MS starting to report serotype data. Sixteen MS met all Salmonella reduction targets for poultry, whereas 12 MS failed meeting at least one. The EU flock prevalence of target Salmonella serovars in breeding hens, laying hens, broilers and fattening turkeys decreased or remained stable compared to 2016, and slightly increased in breeding turkeys. Salmonella results on pig carcases and target Salmonella serovar results for poultry from competent authorities tended to be generally higher compared to those from food business operators. The notification rate of human listeriosis further increased in 2017, despite Listeria seldom exceeding the EU food safety limit in ready-to-eat food. The decreasing EU trend for confirmed yersiniosis cases since 2008 stabilised during 2013-2017. The number of confirmed shiga toxin-producing Escherichia coli (STEC) infections in humans was stable. A total of 5,079 food-borne (including waterborne) outbreaks were reported. Salmonella was the commonest detected agent with S. Enteritidis causing one out of seven outbreaks, followed by other bacteria, bacterial toxins and viruses. The agent was unknown in 37.6% of all outbreaks. Salmonella in eggs and Salmonella in meat and meat products were the highest risk agent/food pairs. The report further summarises trends and sources for bovine tuberculosis, Brucella, Trichinella, Echinococcus, Toxoplasma, rabies, Coxiella burnetii (Q fever), West Nile virus and tularaemia.

Trends in Q fever serologic testing by immunofluorescence from four large reference laboratories in the United States, 2012-2016

Laboratory testing for Q fever (Coxiella burnetii) is essential for a differential diagnosis, yet little is known about Q fever diagnostic testing practices in the United States. We retrospectively analyzed Q fever immunoglobulin G (IgG) indirect immunofluorescence assay (IFA) testing data between 1/1/2012–10/31/2016 from ARUP, LabCorp, Mayo Medical Laboratories, and Quest Diagnostics. Data included IgG phase I and phase II titers, patient age and sex, and state and date of specimen collection. On average, 12,821 specimens were tested for Q fever annually by the participating laboratories. Of 64,106 total specimens, 84.1% tested negative for C. burnetii-specific antibodies. Positive titers ranged from 16 to 262,144 against both phase I and phase II antigens. Submission of specimens peaked during the summer months, and more specimens were submitted from the West North Central division. Testing occurred more frequently in males (53%) and increased with age. In conclusion, few U.S. Q fever cases are reported, despite large volumes of diagnostic specimens tested. Review of commercial laboratory data revealed a lack of paired serology samples and patterns of serology titers that differ from case reporting diagnostic criteria.

A Q Fever Outbreak with a High Rate of Abortions at a Dairy Goat Farm: Coxiella burnetii Shedding, Environmental Contamination, and Viability

This study describes a Q fever outbreak in a herd of 77 Alpine goats which suffered a high rate of abortions (81% [58/72]) in January 2017 and presents the results of monitoring the contamination and viability of Coxiella burnetii in the farm environment several months after the outbreak. Over the course of 7 months, we studied bacterial shedding by 35 dams with abortions to monitor C. burnetii infection dynamics and the duration of excretion. The highest bacterial shedding load was observed in vaginal mucus, followed by in feces and in milk. Conversely, the duration of C. burnetii shedding was longer through feces (5 months after abortion) than milk (3 months). C. burnetii DNA was detected throughout the study in aerosol samples periodically collected indoors and outdoors from the animal premises. Mouse inoculation and culture in Vero cells demonstrated the presence of viable isolates in dust collected from different surfaces inside the animal facilities during the period of time with the highest number of abortions but not in dust collected 2, 3, and 4 months after the last parturition. Some workers and visitors were affected by Q fever, with attack rates of 78% (7/9) and 31% (4/13), respectively. Affected people mostly showed fever and seroconversion, along with myalgia and arthralgia in two patients and pneumonia in the index case. The genotype identified in animal and environmental samples (SNP1/MST13) turned out to be very aggressive in goats but caused only moderate symptoms in people. After the diagnosis of abortion by Q fever in goats, several control measures were implemented at the farm to prevent contamination inside and outside the animal facilities.IMPORTANCE This work describes a 7-month follow-up of the excretion by different routes of Coxiella burnetii genotype SNP1/MST13 in a herd of goats that suffered high rate of abortions (81%), generating high environmental contamination. Some of the workers and visitors who accessed the farm were infected, with fever as the main symptom but a low incidence of pneumonia. The detected strain (SNP1/MST13 genotype) turned out to be very aggressive in goats. The viability of C. burnetii was demonstrated in the environment of the farm at the time of abortions, but 2 months after the last parturition, no viable bacteria were detected. These results highlighted the importance of implementing good biosafety measures at farms and avoiding the entrance of visitors to farms several months after the end of the kidding period.

Serologic Survey and Risk Factors for Coxiella burnetii Infection among Dairy Cattle Farmers in Korea

BACKGROUND

The zoonotic disease Q fever is caused by Coxiella burnetii and usually affects high-risk human populations. We conducted a serological survey of dairy cattle farmers in Korea to determine seroreactivity and identify risk factors for C. burnetii infection.

METHODS

This cross-sectional study included 1,824 of 7,219 dairy cattle farms (25.3%) in the study region. The selected dairy cattle farmers visited the nearest public health centers or branches with completed questionnaires. Serum samples from the farmers were tested using an indirect immunofluorescence assay to detect phase II C. burnetii immunoglobulin (Ig) G or M antibodies.

RESULTS

A total of 1,222 dairy cattle farmers from 784 dairy cattle farms (43.0%) participated in this study, and 11.0% (134/1,222) exhibited seroreactivity, defined as a phase II antigen IgG or IgM titer ≥ 1:16. In the multivariate analysis, male sex, residence in Gyeonggi Province, a larger herd size, and ocular/oral contact with birth products during calf delivery were significantly associated with a higher risk of C. burnetii infection. Furthermore, the risk was significantly lower among farmers who always wore protective gloves while cleaning cattle excretion, compared to those who sometimes or rarely wore protective gloves.

CONCLUSION

Dairy cattle farmers should exercise caution by avoiding ocular/oral contact with birth products during calf delivery and by using protective equipment (including gloves).

Interaction between autophagic vesicles and the Coxiella-containing vacuole requires CLTC (clathrin heavy chain)

Coxiella burnetii is an intracellular bacterial pathogen which causes Q fever, a human infection with the ability to cause chronic disease with potentially life-threatening outcomes. In humans, Coxiella infects alveolar macrophages where it replicates to high numbers in a unique, pathogen-directed lysosome-derived vacuole. This compartment, termed the Coxiella-containing vacuole (CCV), has a low internal pH and contains markers both of lysosomes and autophagosomes. The CCV membrane is also enriched with CLTC (clathrin heavy chain) and this contributes to the success of the CCV. Here, we describe a role for CLTC, a scaffolding protein of clathrin-coated vesicles, in facilitating the fusion of autophagosomes with the CCV. During gene silencing of CLTC, CCVs are unable to fuse with each other, a phenotype also seen when silencing genes involved in macroautophagy/autophagy. MAP1LC3B/LC3B, which is normally observed inside the CCV, is excluded from CCVs in the absence of CLTC. Additionally, this study demonstrates that autophagosome fusion contributes to CCV size as cell starvation and subsequent autophagy induction leads to further CCV expansion. This is CLTC dependent, as the absence of CLTC renders autophagosomes no longer able to contribute to the expansion of the CCV. This investigation provides a functional link between CLTC and autophagy in the context of Coxiella infection and highlights the CCV as an important tool to explore the interactions between these vesicular trafficking pathways.

Q Fever in Military Firefighters during Cadet Training in Brazil

We report five cases of Q fever among cadets during a training program for Military Firefighters Academy in the state of Rio de Janeiro, Brazil. This cluster confirms the significance of Coxiella burnetii as an infectious agent in Brazil, where the occurrence of this zoonosis is poorly documented and highlights the potential risk for Q fever transmission in rural areas or farms with infected animals.

The European Union summary report on trends and sources of zoonoses, zoonotic agents and food-borne outbreaks in 2016

This report of the European Food Safety Authority and the European Centre for Disease Prevention and Control presents the results of the zoonoses monitoring activities carried out in 2016 in 37 European countries (28 Member States (MS) and nine non-MS). Campylobacteriosis was the most commonly reported zoonosis and the increasing European Union (EU) trend for confirmed human cases since 2008 stabilised during 2012-2016. In food, the occurrence of Campylobacter remained high in broiler meat. The decreasing EU trend for confirmed human salmonellosis cases since 2008 ended during 2012-2016, and the proportion of human Salmonella Enteritidis cases increased. Most MS met their Salmonella reduction targets for poultry, except five MS for laying hens. At primary production level, the EU-level flock prevalence of target Salmonella serovars in breeding hens, broilers, breeding and fattening turkeys decreased or stabilised compared with previous years but the EU prevalence of S. Enteritidis in laying hens significantly increased. In foodstuffs, the EU-level Salmonella non-compliance for minced meat and meat preparations from poultry was low. The number of human listeriosis confirmed cases further increased in 2016, despite the fact that Listeria seldom exceeds the EU food safety limit in ready-to-eat foods. The decreasing EU trend for confirmed yersiniosis cases since 2008 stabilised during 2012-2016, and also the number of confirmed Shiga toxin-producing Escherichia coli (STEC) infections in humans was stable. In total, 4,786 food-borne outbreaks, including waterborne outbreaks, were reported. Salmonella was the most commonly detected causative agent - with one out of six outbreaks due to S. Enteritidis - followed by other bacteria, bacterial toxins and viruses. Salmonella in eggs continued to represent the highest risk agent/food combination. The report further summarises trends and sources for bovine tuberculosis, brucellosis, trichinellosis, echinococcosis, toxoplasmosis, rabies, Q fever, West Nile fever and tularaemia.

Estimation of the frequency of Q fever in sheep, goat and cattle herds in France: results of a 3-year study of the seroprevalence of Q fever and excretion level of Coxiella burnetii in abortive episodes

A study was carried out, from 2012 to 2015, in 10 French départements to estimate the serological prevalence of Q fever and the frequency of abortive episodes potentially related to Coxiella burnetii in a large sample of cattle, sheep and goat herds. The serological survey covered 731 cattle, 522 sheep and 349 goat herds, randomly sampled. The frequency of abortive episodes potentially related to C. burnetii was estimated by investigating series of abortions in 2695 cattle, 658 sheep and 105 goat herds using quantitative polymerase chain reaction analyses and complementary serological results when needed. The average between-herd seroprevalence was significantly lower for cattle (36·0%) than for sheep (55·7%) and goats (61·0%) and significantly higher for dairy herds (64·9% for cattle and 75·6% for sheep) than for meat herds (18·9% for cattle and 39·8% for sheep). Within-herd seroprevalence was also significantly higher for goats (41·5%) than for cattle (22·2%) and sheep (25·7%). During the study period, we estimated that 2·7% (n = 90), 6·2% (n = 48) and 16·7% (n = 19) of the abortive episodes investigated could be ‘potentially related to C. burnetii’in cattle, sheep and goat herds, respectively. Overall, strong variability was observed between départements and species, suggesting that risk factors such as herd density and farming practices play a role in disease transmission and maintenance.

A Case of Primary Aortoduodenal Fistula and Abdominal Aortic Aneurysm in a Patient with Chronic Q Fever

A 70-year-old man was successfully treated for an aortoduodenal fistula originating from a Q fever-related abdominal aortic aneurysm. He had no known history of contact with cattle or sheep. Although the combination of abdominal aortic aneurysm and aortoduodenal fistula is rare, one should be suspicious of Q fever infection as the causative agent, and additional medical treatment should be initiated.

Insight into "Calculated Risk": An Application to the Prioritization of Emerging Infectious Diseases for Blood Transfusion Safety

Increasing identification of transmissions of emerging infectious diseases (EIDs) by blood transfusion raised the question which of these EIDs poses the highest risk to blood safety. For a number of the EIDs that are perceived to be a threat to blood safety, evidence on actual disease or transmission characteristics is lacking, which might render measures against such EIDs disputable. On the other hand, the fact that we call them "emerging" implies almost by definition that we are uncertain about at least some of their characteristics. So what is the relative importance of various disease and transmission characteristics, and how are these influenced by the degree of uncertainty associated with their actual values? We identified the likelihood of transmission by blood transfusion, the presence of an asymptomatic phase of infection, prevalence of infection, and the disease impact as the main characteristics of the perceived risk of disease transmission by blood transfusion. A group of experts in the field of infectious diseases and blood transfusion ranked sets of (hypothetical) diseases with varying degrees of uncertainty associated with their disease characteristics, and used probabilistic inversion to obtain probability distributions for the weight of each of these risk characteristics. These distribution weights can be used to rank both existing and newly emerging infectious diseases with (partially) known characteristics. Analyses show that in case there is a lack of data concerning disease characteristics, it is the uncertainty concerning the asymptomatic phase and the disease impact that are the most important drivers of the perceived risk. On the other hand, if disease characteristics are well established, it is the prevalence of infection and the transmissibility of the disease by blood transfusion that will drive the perceived risk. The risk prioritization model derived provides an easy to obtain and rational expert assessment of the relative importance of an (emerging) infectious disease, requiring only a limited amount of information. Such a model might be used to justify a rational and proportional response to an emerging infectious disease, especially in situations where little or no specific information is available.

Are brucellosis, Q fever and melioidosis potential causes of febrile illness in Madagascar?

Brucellosis, Q fever and melioidosis are zoonoses, which can lead to pyrexia. These diseases are often under-ascertained and underreported because of their unspecific clinical signs and symptoms, insufficient awareness by physicians and public health officers and limited diagnostic capabilities, especially in low-resource countries. Therefore, the presence of Brucella spp., Coxiella burnetii and Burkholderia pseudomallei was investigated in Malagasy patients exhibiting febrile illness. In addition, we analyzed zebu cattle and their ticks as potential reservoirs for Brucella and C. burnetii, respectively. Specific quantitative real-time PCR assays (qPCRs) were performed on 1020 blood samples drawn from febrile patients. In total, 15 samples (1.5%) were Brucella-positive, mainly originating from patients without travel history, while DNA from C. burnetii and Bu. pseudomallei was not detected. Anti-C. burnetii antibodies were found in four out of 201 zebu serum samples (2%), whereas anti-Brucella antibodies could not be detected. Brucella DNA was detected in a single zebu sample. Three out of 330 ticks analyzed (1%) were positively tested for C. burnetii DNA but with high Ct values in the qPCR assay. Our data suggest that zebus as well as Amblyomma and Boophilus ticks have to be considered as a natural reservoir or vector for C. burnetii, but the risk of cattle-to-human transmission is low. Since bovine brucellosis does not seem to contribute to human infections in Madagascar, other transmission routes have to be assumed.

The Epidemiology of Q Fever in England and Wales 2000-2015

Between 2000 and 2015, 904 cases of acute Q fever were reported in England and Wales. The case dataset had a male to female ratio of 2.5:1, and a median age of 45 years. Two outbreaks were recognised during this time period, and the incidence of sporadic cases was highest across the southwest of England, and Wales. There are limitations in the surveillance system for Q fever, including possible geographical differences in reporting and limited epidemiological data collection. The surveillance system needs to be strengthened in order to improve the quality and completeness of the epidemiological dataset. The authors conclude with recommendations on how to achieve this.

From Q Fever to Coxiella burnetii Infection: a Paradigm Change

Coxiella burnetii is the agent of Q fever, or "query fever," a zoonosis first described in Australia in 1937. Since this first description, knowledge about this pathogen and its associated infections has increased dramatically. We review here all the progress made over the last 20 years on this topic. C. burnetii is classically a strict intracellular, Gram-negative bacterium. However, a major step in the characterization of this pathogen was achieved by the establishment of its axenic culture. C. burnetii infects a wide range of animals, from arthropods to humans. The genetic determinants of virulence are now better known, thanks to the achievement of determining the genome sequences of several strains of this species and comparative genomic analyses. Q fever can be found worldwide, but the epidemiological features of this disease vary according to the geographic area considered, including situations where it is endemic or hyperendemic, and the occurrence of large epidemic outbreaks. In recent years, a major breakthrough in the understanding of the natural history of human infection with C. burnetii was the breaking of the old dichotomy between "acute" and "chronic" Q fever. The clinical presentation of C. burnetii infection depends on both the virulence of the infecting C. burnetii strain and specific risks factors in the infected patient. Moreover, no persistent infection can exist without a focus of infection. This paradigm change should allow better diagnosis and management of primary infection and long-term complications in patients with C. burnetii infection.

Analysis of the Caenorhabditis elegans innate immune response to Coxiella burnetii

The nematode Caenorhabditis elegans is well established as a system for characterization and discovery of molecular mechanisms mediating microbe-specific inducible innate immune responses to human pathogens. Coxiella burnetii is an obligate intracellular bacterium that causes a flu-like syndrome in humans (Q fever), as well as abortions in domesticated livestock, worldwide. Initially, when wild type C. elegans (N2 strain) was exposed to mCherry-expressing C. burnetii (CCB) a number of overt pathological manifestations resulted, including intestinal distension, deformed anal region and a decreased lifespan. However, nematodes fed autoclave-killed CCB did not exhibit these symptoms. Although vertebrates detect C. burnetii via TLRs, pathologies in tol-1(-) mutant nematodes were indistinguishable from N2, and indicate nematodes do not employ this orthologue for detection of C. burnetii. sek-1(-) MAP kinase mutant nematodes succumbed to infection faster, suggesting that this signaling pathway plays a role in immune activation, as previously shown for orthologues in vertebrates during a C. burnetii infection. C. elegans daf-2(-) mutants are hyper-immune and exhibited significantly reduced pathological consequences during challenge. Collectively, these results demonstrate the utility of C. elegans for studying the innate immune response against C. burnetii and could lead to discovery of novel methods for prevention and treatment of disease in humans and livestock.

Coxiella burnetii dormancy in a fatal ten-year multisystem dysfunctional illness: case report

BACKGROUND

In a previous study of a Q fever outbreak in Birmingham, our group identified a non-infective complex of Coxiella burnetii (C.b.) antigens able to survive in the host and provoked aberrant humoral and cell-mediated immunity responses. The study led to recognition of a possible pathogenic link between C.b. infection and subsequent long-term post Q fever fatigue syndrome (QFS). This report presents an unusually severe case of C.b. antigen and DNA detection in post-mortem specimens from a patient with QFS.

CASE PRESENTATION

We report a 19-year old female patient who became ill with an acute unexplained febrile encephalitis-like illness, followed by increasingly severe multisystem dysfunction and death 10 years later. During life, extensive clinical and laboratory investigations from different disciplinary stand points failed to deliver a definitive identification of a cause. Given the history of susceptibility to infection from birth, acute fever and the diagnosis of "post viral syndrome", tests for infective agents were done starting with C.b. and Legionella pneumophila. The patient had previously visited farms a number of times. Comprehensive neuropathological assessment at the time of autopsy had not revealed gross or microscopic abnormalities. The aim was to extend detailed studies with the post-mortem samples and identify possible factors driving severe disturbance of homeostasis and organ dysfunction exhibited by the course of the patient's ten-year illness. Immunohistochemistry for C.b. antigen and PCR for DNA were tested on paraffin embedded blocks of autopsy tissues from brain, spleen, liver, lymph nodes (LN), bone marrow (BM), heart and lung. Standard H&E staining of brain sections was unrevealing. Immuno-staining analysis for astrocyte cytoskeleton proteins using glial fibrillary acidic protein (GFAP) antibodies showed a reactive morphology. Coxiella antigens were demonstrated in GFAP immuno-positive grey and white matter astrocytes, spleen, liver, heart, BM and LN. PCR analysis (COM1/IS1111 genes) confirmed the presence of C.b. DNA in heart, lung, spleen, liver & LN, but not in brain or BM.

CONCLUSION

The study revealed the persistence of C. b. cell components in various organs, including astrocytes of the brain, in a post-infection QFS. The possible mechanisms and molecular adaptations for this alternative C.b. life style are discussed.

Detection of Coxiella burnetii in Ambient Air after a Large Q Fever Outbreak

One of the largest Q fever outbreaks ever occurred in the Netherlands from 2007-2010, with 25 fatalities among 4,026 notified cases. Airborne dispersion of Coxiella burnetii was suspected but not studied extensively at the time. We investigated temporal and spatial variation of Coxiella burnetii in ambient air at residential locations in the most affected area in the Netherlands (the South-East), in the year immediately following the outbreak. One-week average ambient particulate matter < 10 μm samples were collected at eight locations from March till September 2011. Presence of Coxiella burnetii DNA was determined by quantitative polymerase chain reaction. Associations with various spatial and temporal characteristics were analyzed by mixed logistic regression. Coxiella burnetii DNA was detected in 56 out of 202 samples (28%). Airborne Coxiella burnetii presence showed a clear seasonal pattern coinciding with goat kidding. The spatial variation was significantly associated with number of goats on the nearest goat farm weighted by the distance to the farm (OR per IQR: 1.89, CI: 1.31-2.76). We conclude that in the year after a large Q fever outbreak, temporal variation of airborne Coxiella burnetii is suggestive to be associated with goat kidding, and spatial variation with distance to and size of goat farms. Aerosol measurements show to have potential for source identification and attribution of an airborne pathogen, which may also be applicable in early stages of an outbreak.

Persistence of impaired health status of Q fever patients 4 years after the first Dutch outbreak

A significant proportion of Q fever patients from the first Dutch Q fever outbreak in 2007 showed impairment in health status up to 1 year after infection. Interested in whether this decrease in health status persisted, we set out to determine the health status in the same cohort of patients, 4 years after primary infection and to compare health status scores at the individual patient level between 1 and 4 years follow-up. Health status was assessed with the Nijmegen Clinical Screening Instrument (NCSI). Patients were serologically tested to exclude patients with possible, probable or proven chronic Q fever. Results on the NCSI sub-domains at group level [2008 (n = 54) and 2011 (n = 46)] showed a persistent significant percentage of patients exhibiting clinically relevant (‘severe’) scores for all NCSI sub-domains. After 4 years, undue fatigue was present in 46% and exactly half of all patients experienced a severely impaired general quality of life. Patients with NCSI scores available in both 2008 and 2011 (n = 37) showed no difference in all sub-domain scores, except for a small decrease in dyspnoea emotions in 2011. In this group, a significant proportion of patients either improved or worsened in one or more sub-domains of health status. We conclude that at the group level, health status of Q fever patients remained impaired 4 years after primary infection. At the individual patient level, health status may change.

Delayed diagnosis of Q fever endocarditis in a rheumatoid arthritis patient

Chronic Q fever caused by Coxiella burnetii is uncommon in the United States and is most often associated with infective endocarditis. We present a 52-year-old woman with a history of aortic valve replacement and rheumatoid arthritis treated with Etanercept with chronic Q fever manifesting as prosthetic valve infective endocarditis. Explanted valve tissue showed organisms confirmed to be C. burnetii by PCR (polymerase chain reaction) sequencing. She subsequently reported consumption of unpasteurized cow milk which was the likely source of C. burnetii. She continues to do well 6 months after valve replacement on oral doxycycline and hydroxychloroquine.

First Draft Genome Sequence of a Human Coxiella burnetii Isolate, Originating from the Largest Q Fever Outbreak Ever Reported, the Netherlands, 2007 to 2010

In 2009, Coxiella burnetii caused a large regional outbreak of Q fever in South Limburg, the Netherlands. Here, we announce the genome draft sequence of a human C. burnetii isolate, strain NL-Limburg, originating from this outbreak, including a brief summary of the genome’s general features.